Abstract

A novel combination of adaptive optics with a simultaneous en-face OCT/SLO system for high resolution imaging of the in-vivo human retina is presented. Pairs of retinal images are shown and performance of the system is evaluated with and without dynamic wavefront correction. The adaptive optics closed loop system operates at a frame rate of 9 Hz and incorporates a Shack-Hartmann wavefront sensor based on a highly sensitive Andor camera and a 37 actuator OKO membrane deformable mirror to correct for ocular aberrations. The system produces C-scan pairs of images at a frame rate of 2 Hz. The correction of aberrations produced by the adaptive optics closed-loop system increased the signal-to-noise ratio in images obtained from volunteer eyes by up to 6 dB in the OCT channel and up to 9 dB in the SLO channel. A slight improvement in the lateral resolution was also obtained, from 6.5 μm before to 5 μm after closing the adaptive optics loop.

The graph on the left shows the temporal evolution of the reconstructed RMS before and immediately after the AO closed-loop system is turned on. On the right, the PSF and reconstructed wavefront without adaptive optics correction (top) and with adaptive optics correction (bottom) are shown.

Longitudinal OCT images obtained from the right eye of the volunteer (AB) before and after applying adaptive optics correction. The images are from a patch of the retina at 5 deg from the subject’s fovea in the nasal direction. On the right, the average of the grey levels performed along the x axis shows an improvement in the signal strength due to correction.

En-face OCT and SLO images obtained from the same area of the DM’s retina, before and after applying adaptive correction. The size of the retinal patch imaged is 330×500 μm, and the pixel size is 1×1 μm. The depth selected is at the photoreceptor level.